"What brought that up?"
Rose turned around, nodding towards the tree. "We've been going in circles. I've seen that tree before."
"Ah." The Doctor scanned the tree with his screwdriver. "It's a bit like low budget films and animation where they reuse the backgrounds."
"We're stuck in an episode of Scooby Doo?" Rose looked confused.
"No. When they terra-formed this planet, they did it on the cheap. The trees were clones of a single species. Explains why this is nearly a dead planet."
dw100 — challenge #170: familiar